[net-next-2.6.git] / drivers / watchdog / ixp2000_wdt.c

/*
 * drivers/char/watchdog/ixp2000_wdt.c
 *
 * Watchdog driver for Intel IXP2000 network processors
 *
 * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
 * The original version carries these notices:
 *
 * Author: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright 2004 (c) MontaVista, Software, Inc.
 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <mach/hardware.h>

static int nowayout = WATCHDOG_NOWAYOUT;
static unsigned int heartbeat = 60;	/* (secs) Default is 1 minute */
static unsigned long wdt_status;
static spinlock_t wdt_lock;

#define	WDT_IN_USE		0
#define	WDT_OK_TO_CLOSE		1

static unsigned long wdt_tick_rate;

static void wdt_enable(void)
{
	spin_lock(&wdt_lock);
	ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
	ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
	ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
	spin_unlock(&wdt_lock);
}

static void wdt_disable(void)
{
	spin_lock(&wdt_lock);
	ixp2000_reg_write(IXP2000_T4_CTL, 0);
	spin_unlock(&wdt_lock);
}

static void wdt_keepalive(void)
{
	spin_lock(&wdt_lock);
	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
	spin_unlock(&wdt_lock);
}

static int ixp2000_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
		return -EBUSY;

	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	wdt_enable();

	return nonseekable_open(inode, file);
}

static ssize_t ixp2000_wdt_write(struct file *file, const char *data,
						size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
			}
		}
		wdt_keepalive();
	}

	return len;
}


static const struct watchdog_info ident = {
	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
				WDIOF_KEEPALIVEPING,
	.identity	= "IXP2000 Watchdog",
};

static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	int ret = -ENOTTY;
	int time;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info *)arg, &ident,
				   sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_KEEPALIVE:
		wdt_enable();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, (int *)arg);
		if (ret)
			break;

		if (time <= 0 || time > 60) {
			ret = -EINVAL;
			break;
		}

		heartbeat = time;
		wdt_keepalive();
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, (int *)arg);
		break;
	}

	return ret;
}

static int ixp2000_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		wdt_disable();
	else
		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
					"timer will not stop\n");
	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
}


static const struct file_operations ixp2000_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= ixp2000_wdt_write,
	.unlocked_ioctl	= ixp2000_wdt_ioctl,
	.open		= ixp2000_wdt_open,
	.release	= ixp2000_wdt_release,
};

static struct miscdevice ixp2000_wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &ixp2000_wdt_fops,
};

static int __init ixp2000_wdt_init(void)
{
	if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
		printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
		return -EIO;
	}
	wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
	spin_lock_init(&wdt_lock);
	return misc_register(&ixp2000_wdt_miscdev);
}

static void __exit ixp2000_wdt_exit(void)
{
	misc_deregister(&ixp2000_wdt_miscdev);
}

module_init(ixp2000_wdt_init);
module_exit(ixp2000_wdt_exit);

MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
1da177e4	1	/*
f30c2269	2	* drivers/char/watchdog/ixp2000_wdt.c
1da177e4 LT	3	*
	4	* Watchdog driver for Intel IXP2000 network processors
	5	*
	6	* Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
	7	* The original version carries these notices:
	8	*
	9	* Author: Deepak Saxena <dsaxena@plexity.net>
	10	*
	11	* Copyright 2004 (c) MontaVista, Software, Inc.
	12	* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
	13	*
	14	* This file is licensed under the terms of the GNU General Public
	15	* License version 2. This program is licensed "as is" without any
	16	* warranty of any kind, whether express or implied.
	17	*/
	18
1da177e4 LT	19	#include <linux/module.h>
	20	#include <linux/moduleparam.h>
	21	#include <linux/types.h>
e605d554	22	#include <linux/timer.h>
1da177e4 LT	23	#include <linux/kernel.h>
	24	#include <linux/fs.h>
	25	#include <linux/miscdevice.h>
	26	#include <linux/watchdog.h>
	27	#include <linux/init.h>
	28	#include <linux/bitops.h>
640b4f68	29	#include <linux/uaccess.h>
a09e64fb	30	#include <mach/hardware.h>
1da177e4	31
4bfdf378	32	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	33	static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
1da177e4 LT	34	static unsigned long wdt_status;
640b4f68	35	static spinlock_t wdt_lock;
1da177e4 LT	36
	37	#define WDT_IN_USE 0
	38	#define WDT_OK_TO_CLOSE 1
	39
	40	static unsigned long wdt_tick_rate;
	41
640b4f68	42	static void wdt_enable(void)
1da177e4	43	{
640b4f68	44	spin_lock(&wdt_lock);
1da177e4 LT	45	ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) \| WDT_RESET_ENABLE);
	46	ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
	47	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
	48	ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 \| TIMER_ENABLE);
640b4f68	49	spin_unlock(&wdt_lock);
1da177e4 LT	50	}
1da177e4 LT	51
640b4f68	52	static void wdt_disable(void)
1da177e4	53	{
640b4f68	54	spin_lock(&wdt_lock);
1da177e4	55	ixp2000_reg_write(IXP2000_T4_CTL, 0);
640b4f68	56	spin_unlock(&wdt_lock);
1da177e4 LT	57	}
1da177e4 LT	58
640b4f68	59	static void wdt_keepalive(void)
1da177e4	60	{
640b4f68	61	spin_lock(&wdt_lock);
1da177e4	62	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
640b4f68	63	spin_unlock(&wdt_lock);
1da177e4 LT	64	}
1da177e4 LT	65
640b4f68	66	static int ixp2000_wdt_open(struct inode inode, struct file file)
1da177e4 LT	67	{
	68	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	69	return -EBUSY;
	70
	71	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	72
	73	wdt_enable();
	74
	75	return nonseekable_open(inode, file);
	76	}
	77
640b4f68 AC	78	static ssize_t ixp2000_wdt_write(struct file file, const char data,
640b4f68 AC	79	size_t len, loff_t *ppos)
1da177e4 LT	80	{
	81	if (len) {
	82	if (!nowayout) {
	83	size_t i;
	84
	85	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	86
	87	for (i = 0; i != len; i++) {
	88	char c;
	89
	90	if (get_user(c, data + i))
	91	return -EFAULT;
	92	if (c == 'V')
	93	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	94	}
	95	}
	96	wdt_keepalive();
	97	}
	98
	99	return len;
	100	}
	101
	102
42747d71	103	static const struct watchdog_info ident = {
1da177e4 LT	104	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	105	WDIOF_KEEPALIVEPING,
	106	.identity = "IXP2000 Watchdog",
	107	};
	108
640b4f68 AC	109	static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
640b4f68 AC	110	unsigned long arg)
1da177e4	111	{
795b89d2	112	int ret = -ENOTTY;
1da177e4 LT	113	int time;
	114
	115	switch (cmd) {
	116	case WDIOC_GETSUPPORT:
	117	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	118	sizeof(ident)) ? -EFAULT : 0;
	119	break;
	120
	121	case WDIOC_GETSTATUS:
	122	ret = put_user(0, (int *)arg);
	123	break;
	124
	125	case WDIOC_GETBOOTSTATUS:
	126	ret = put_user(0, (int *)arg);
	127	break;
	128
0c06090c WVS	129	case WDIOC_KEEPALIVE:
	130	wdt_enable();
	131	ret = 0;
	132	break;
	133
1da177e4 LT	134	case WDIOC_SETTIMEOUT:
	135	ret = get_user(time, (int *)arg);
	136	if (ret)
	137	break;
	138
	139	if (time <= 0 \|\| time > 60) {
	140	ret = -EINVAL;
	141	break;
	142	}
	143
	144	heartbeat = time;
	145	wdt_keepalive();
	146	/* Fall through */
	147
	148	case WDIOC_GETTIMEOUT:
	149	ret = put_user(heartbeat, (int *)arg);
	150	break;
1da177e4 LT	151	}
	152
	153	return ret;
	154	}
	155
640b4f68	156	static int ixp2000_wdt_release(struct inode inode, struct file file)
1da177e4	157	{
640b4f68	158	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
1da177e4	159	wdt_disable();
640b4f68	160	else
b36bbb6c	161	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
1da177e4	162	"timer will not stop\n");
1da177e4 LT	163	clear_bit(WDT_IN_USE, &wdt_status);
	164	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	165
	166	return 0;
	167	}
	168
	169
640b4f68	170	static const struct file_operations ixp2000_wdt_fops = {
1da177e4 LT	171	.owner = THIS_MODULE,
	172	.llseek = no_llseek,
	173	.write = ixp2000_wdt_write,
640b4f68	174	.unlocked_ioctl = ixp2000_wdt_ioctl,
1da177e4 LT	175	.open = ixp2000_wdt_open,
	176	.release = ixp2000_wdt_release,
	177	};
	178
640b4f68	179	static struct miscdevice ixp2000_wdt_miscdev = {
1da177e4	180	.minor = WATCHDOG_MINOR,
2dab3cab	181	.name = "watchdog",
1da177e4 LT	182	.fops = &ixp2000_wdt_fops,
	183	};
	184
	185	static int __init ixp2000_wdt_init(void)
	186	{
e4fe1981 LB	187	if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
	188	printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
	189	return -EIO;
	190	}
e4fe1981	191	wdt_tick_rate = (IXP2000_T1_CLD HZ) / 256;
640b4f68	192	spin_lock_init(&wdt_lock);
1da177e4 LT	193	return misc_register(&ixp2000_wdt_miscdev);
	194	}
	195
	196	static void __exit ixp2000_wdt_exit(void)
	197	{
	198	misc_deregister(&ixp2000_wdt_miscdev);
	199	}
	200
	201	module_init(ixp2000_wdt_init);
	202	module_exit(ixp2000_wdt_exit);
	203
632155e6	204	MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
1da177e4 LT	205	MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
	206
	207	module_param(heartbeat, int, 0);
	208	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
	209
	210	module_param(nowayout, int, 0);
	211	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	212
	213	MODULE_LICENSE("GPL");
	214	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	215